Question

Light from a sodium lamp `(lambda_0=589 nm)` passes through a tank of glycerin (refractive index `=1.47`) `20m` long in a time `t_1.` If it takes a time `t_2` to transverse the same tank when filled with carbon disulfide (index`=1.63`), determine the difference `t_2-t_1.`

Answer 1

Correct Answer - A
`t_1=l/v_1=l/(c//mu_1)=(mu_1l)/e rArr t_2=(mu_2l)/c`
`:. t_2-t_1=(mu_2-mu_1)l/c`
`=((1.63-1.47)(20))/(3xx10^8)`
`=1.07xx10^-8 s`